How does a wave move along a rope?

[Dunkaroos]

Please help. I'm having difficulty with this problem. My book offers an answer but no explanation. Thanks for helping.I have the answer if you guys want it.

 

[pizzasky]

Note that the wave is moving to the right. Hence, translate the whole curve slightly to the right to determine where point P will eventually be.

 

[kudos213]

Yes, but doesn't each point on the wave maintain it's position in the positive x direction? It's only the y component of each point which changes. Anyone else have any idea?

 

[Hootenanny]

Yes, but doesn't each point on the wave maintain it's position in the positive x direction? It's only the y component of each point which changes. Anyone else have any idea?

Yes, the point P oscillates only in the y direction, so as the wave moves to the right, will point P move up or down?

~H

 

[kudos213]

negative y hat

 

[Hootenanny]

negative y hat

Yes, I suggest we let the OP finish of the question.

~H

 

[kudos213]

word...i'm still new here i.e. learning the ropes. how could we mathematically solved this question?

 

[Hootenanny]

word...i'm still new here i.e. learning the ropes. how could we mathematically solved this question?

You couldn't, there is no data given (velocity/ displacement / time).

~H

 

[DaveC426913]

This question actually somewhat ambiguous, and as such the OP might get the wrong advice and answer.

Depending on how you interpret "point P", your answer will be different!
a] Point P is a physical point on the rope.
b] Point P is an imaginary point on the wave.

Pizzasky interpreted it as a], but others interpreted it as b].

I'm am 99.9% certain a] is correct. So, yes, follow Kudos and Hoot's guidance.

 

[Hootenanny]

This question actually somewhat ambiguous, and as such the OP might get the wrong advice and answer.

Depending on how you interpret "point P", your answer will be different!
a] Point P is a physical point on the rope.
b] Point P is an imaginary point on the wave.

Pizzasky interpreted it as a], but others interpreted it as b].

I'm am 99.9% certain a] is correct. So, yes, follow Kudos and Hoot's guidance.

The OP said they have the correct answer, it would be helpful if he/she could post it to clear the matter up. But I agree with Dave, it is an ambiguous question, I was assuming point P is a physical point on the wave.

~H

 

[skywolf]

if the wave is going to the right, then shouldn't the answer be c?
...
maybe I am missing something

 

[Hootenanny]

if the wave is going to the right, then shouldn't the answer be c?
...
maybe I am missing something

That is what we were discussing, I'll refer you to posts #4,5,6,7

~H

 

[Dunkaroos]

The answer key gives choice C.

Anyone care to explain? Thank you all.

 

[DaveC426913]

OK. That clears up what they're asking. Point P is a physical point on the rope. Pretend it's a spot of paint.

Now, as the wave travels down the rope, how will that spot of paint move?

Think of this: the rope is tied off the right side to a lamppost. Your friend is off to the left, holding the rope, waving it up and down, creating the wave. (Note that the rope does not actually go anywhere - he can wave all he wants, but the rope will remain in our field of vision).

NOW what will the spot of paint do?